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Advisor(s)
Abstract(s)
In the recent past a considerable body of work has been published on the
measurement of activity coefficients and solubility data in aqueous amino
acid solutions containing electrolytes [1]. However, no information on water
activity in this type of system has yet been published [2].
In this work water activity (aw) in DL-alanine, glycine or L-serine aqueous
systems with ammonium sulfate, at 298.15 K, was measured. The
LabMASTER-aw water activity instrument (Novasina, Switzerland) was
used to perform the measurements. The instrument, with a controlled
chamber temperature (± 0.2 K), shows high precision (± 0.001 aw units).
The new experimental data was used to test different theoretical schemes
such as Zdanovskii-Stokes-Robinson (ZSR) model [3] and its extension, or
the Clegg-Seinfeld-Brimblecombe (CSB) approach [4], in the calculation of
amino acid and electrolyte activity coefficients in those solutions.
Comparisons between the different approaches are given.
Description
Keywords
Water activity Electrolyte Amino acids Measurement
Citation
Fernandes, Isa; Vilarinho, Mário; Pinho, Simão (2008). Experimental and theoretical studies on water activity: aqueous solutions of amino acids with electrolytes. In 23rd European Symposium on Applied Thermodynamics. Cannes